Every organ and every cell has their own, distinctive oscillation which is detected and stored in the ETAScan computer memory, which is displayed as a graph representing the conditions of the information exchange between the tissue and the environment. Every pathological process has its own distinctive individual graph. A great number of pathological processes relating to degree, age, sex and other variables are stored in the computer memory. the investigation device can compare the degree of their spectrum similarity to reference processes (healthy, pathology-affected tissues, infection agents) after reading the frequency characteristics of the biological object and define the closest pathological process or a tendency to its origin.